Field of the Invention
The present invention relates to a liquid ejection head and an inkjet printing apparatus, and more particularly, a technique of increasing a strength of a member forming a liquid flow path in a liquid ejection head.
Description of the Related Art
As such a type of technique, Japanese Patent Laid-Open No. 2007-283501 discloses a technique in which a reinforcing member is provided to a portion of the member, which forms a liquid flow path of a liquid ejection head and faces a liquid supply port. More specifically, in the disclosed technique, a beam-shaped protrusion is provided to a portion of a flow path forming member facing the liquid supply port which is a cavity formed through a substrate of the liquid ejection head so as to increase a thickness toward the substrate, and reinforcing ribs are provided to extend from the beam-shaped protrusion so as to approach a flow path communicating with an ejection opening.
According to the above structure, when a force deforming the flow path forming member toward the substrate is exerted on the flow path forming member, the deformation can be prevented by allowing the reinforcing ribs to be in contact with the substrate, and as a result, the strength of the flow path forming member can be further increased.
However, in the case of a liquid ejection head where ejection openings are arranged with a relatively high density, the arrangement of the reinforcing ribs may cause adverse effects. More specifically, the reinforcing ribs are arranged with a high density, and thus, a space surrounded by the reinforcing rib and the ink flow path that communicates with the ejection opening, that is, a communicating passage between the ink flow path and the liquid supply port is narrowed, so that flow of liquid between each ink flow path and the liquid supply port is obstructed. As a result, for example, circulation of liquid between the ink flow path and the liquid supply port is suppressed, and thus, ink thickening or the like occurs, so that ejection performance may be deteriorated.